Target Size Variation in Microdosimetric Distributions and its Impact on the Linear-Quadratic Parameterization of Cell Survival

• DOI: 10.1667/rr15089.1
• Publication Date: 2018-08-14T09:10:35Z
• Authors: Fernanda Villegas; Nina Tilly; Anders Ahnesjö
• Keywords: Linear energy transfer; Radiobiology

The linear-quadratic (LQ) parameterization of survival fraction [SF(D)] inherently assumes that all cells in a population receive the same dose (D), albeit distribution specific energy z over individual f(z,D) can be very wide. From these microdosimetric distributions, which are target size dependent, we estimate cellular sensitive volume by analyzing its influence on LQ cell survival. A Monte Carlo track structure code was used to simulate detailed tracks from 60Co source as well proton and carbon ions various energies. tracks, distributions were calculated for spherical targets with diameters ranging 10 nm 12 μm. function based fitted experimental α values, revealing an intrinsic limitation imposes usage describe linear term parameterization. results indicate such threshold arises naturally relationship between particle's probability no-hit Further analysis led proposal radiobiological property , defined mean lineal corresponding allows equivalence inactivation (MID) . fact is increasing continuous within range biological interest radiobiology, ensures uniqueness any radiation quality, thus, potential usefulness modeling. In conclusion, accurate estimation volumes may useful improving modeling curves.